Method of sealing the stopping and withdrawing head in a continuous casting mold

ABSTRACT

A method of sealing the stopping and withdrawing head in a continuous casting mold wherein movable mold wall means of the continuous casting mold are displaced from a casting position away from the longitudinal casting axis so as to open the continuous casting mold, the stopping and withdrawing head is then introduced into the open continuous casting mold until it has assumed a prescribed position within such casting mold, and with a seal or seal member located intermediate the clearance gap between the stopping and withdrawing head and the walls of the casting mold, and finally the clearance gap is sealed through the action of the seal member by returning the mold walls into casting position. It is possible to either apply the seal member to the stopping and withdrawing head prior to the time that the latter is introduced into the open continuous casting mold or after such stopping and withdrawing head has already been introduced into the casting mold.

United States Patent 1 1 3,799,238

Bruderer et al. Mar. 26, 1974 METHOD OF SEALING THE STOPPING Primary Examiner-R. Spencer Annear AND WITHDRAWING HEAD IN A Attorney, Agent, or Firm-Werner W. Kleeman CONTINUOUS CASTING MOLD [75] Inventors: Werner Bruderer, Feldmeilen; Peter [57] ABSTRACT J. Koenig, Zumikon, both of Switzerland A method of sealing the stopping and w thdrawing head in a continuous casting mold wherein movable Assigneel Collcflsl Zurich, Switzerland mold wall means of the continuous casting mold are [22] Ffled: 23, 1972 displaced from a casting position away from the longitudinal casting axis so as to open the continuous cast- PP 223,765 a ing mold, the stopping and withdrawing head is then introduced into the open continuous casting mold until it has assumed a prescribed position within such [30] Foreign Application Priority Data F b 25 197] switz fland 2881/71 casting mold, and with a seal or seal member located 8 e intermediate the clearance gap between the stopping and withdrawing head and the walls of the casting lot/2:325;d 6 11/12/33 mold and finally the clearance gap is sealed through Fieid 274 282 the action of the seal member by returning the mold r walls into casting position. It is possible to either apply the seal member to the stopping and withdrawing head [56] References C'ted prior to the time that the latter is introduced into the UNITED STATES PATENTS open continuous casting mold or after such stopping 3,528,485 9/1970 Vogel 164/82 X and withdrawing head has already been introduced 3,559,720 2/1971 Vogel et al. 164/82 X into the casting 3,643,731 2/]972 Stull A. 164/274 10 Claims, 3 Drawing Figures METHOD OF SEALING THE STOPPING AND WITHDRAWING HEAD IN A CONTINUOUS CASTING MOLD BACKGROUND OF THE INVENTION The present invention relates to a new and improved method of sealing the stopping and withdrawing head in a continuous casting mold having movable walls defining the cross-section of the mold interior or casting cavity of the mold, the walls of the mold being adjusted to the dimensions of the desired casting, and wherein a seal is inserted into the clearance gap between the stopping and withdrawing head and the mold walls.

In the case of continuous casting molds having movable walls it has already been proposed to adjust at least some of the walls to the cross-section of the casting prior to the pouring or casting operation and then to convey the stopping and withdrawing head into the desired position inside of the mold. Introduction of this stopping and withdrawing head may be effected through the outlet end of the continuous casting mold through which the casting emerges or through the open end of the mold into which the melt is poured. In order to enable the stopping and withdrawing head to be thus introduced into the mold the external dimensions of the stopping and withdrawing head should be slightly smaller than the internal dimensions of the mold cavity. A clearance gap thus remains between the stopping and withdrawing head and the internal walls of the mold which, as such, would permit the poured metal to run out of the mold. This is typically prevented by sealing the clearance gap with tightly rammed sealing cords. When high-melting metals are cast such as steel, the sealing effect of the sealing cards is partly nullified by the formation of cracks and by slagging at the high prevailing temperatures and the liquid steel may therefore break-out, the drawbacks of such metal break-out being well known to those versed in the continuous casting art. In order to prevent this from happening the seal is additionally covered with chill scrap which prevents the destruction of the seal until there has formed a solidified or frozen support or bearing layer of metal over the seal.

The sealing and covering operations must be carried out very carefully and this, in turn, results in a very significant loss in time between consecutive pours. If the seal is not carefully prepared it is quite possible for metal break-out to occur when casting or pouring begins and for all the unpleasant consequences thereof to be thenpresent.

SUMMARY OF THE INVENTION With the foregoing discussion in mind it should be recognized that the continuous casting art is still in need of techniques for sealing the stopping and withdrawing head in a continuous casting mold in a manner not associated with the previously discussed drawbacks and limitations of the prior art proposals. Therefore it is a primary objective of this invention to provide a sealing technique for the stopping and withdrawing head of a continuous casting mold which is free of the aforementioned drawbacks and limitations of the stateof-the-art proposals.

Another and more specific object of the present invention relates to a new and improved method of sealing the stopping and withdrawing head of a continuous casting mold with minimum loss in time while nonetheless insuring for the provision of a really reliable and satisfactory seal.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the method aspects of this development contemplates withdrawing at least two adjoining mold walls from their casting position away from the longitudinal casting axis, introducing the stopping and withdrawing head into its prescribed position within the casting mold, and sealing the clearance gap between the stopping and withdrawing head and the mold walls by returning the mold walls into casting position.

BRIEF DESCRIPTION OF THE DRAWING The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed into casting position and the seal, which after its deformation due to displacing the walls of the mold back into casting position, fills out the gap between such mold walls and the stopping and withdrawing head of the dummy bar.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the invention in greater detail, and considering the drawing it is to be assumed that there is employed an open-ended continuous casting mold 7 having at least two adjoining mold walls, such as the molds walls 4, S, 6 shown in the drawings (only one of the narrow mold walls 6 is visible in the drawings), which can be displaced away from their normal casting position. It is thought to be unnecessary to illustrate in any great detail the casting equipment since continuous casting molds having at leastone movable mold wall are already known to the art, as exemplified for instance in the commonly assigned copending U.S'. Pat. Application Ser. No. l27,593 and entitled Adjustable Continuous Casting Mold, filed Mar. 24, 1971, to which reference .may be readily had. The inventive technique of sealing the stopping and withdrawing head 8 of the dummy or starter bar 1 in such continuous casting mold 7 having the movable walls 4-6 defining the cross-section of the mold cavity or mold interior 9 contemplates withdrawing at least two adjoining mold walls from their casting position away from the longitudinal casting axis, as indicated by the arrows 16 in FIG. 1. Then the stopping and withdrawing head 8 is introduced in the direction of the arrow 15 into the thus adjusted casting mold 7 so as to assume the desired or prescribed position. The stopping and withdrawing head 8 can be introduced into the casting mold 7 either before the seal 2 is applied thereto or the seal may be applied to the stopping and withdrawing head 8 prior to introduction of the latter into its prescribed position within the casting mold 7. Regardless of which technique is employed, and following the correct positioning of the stopping and withdrawing head 8 of the starter bar 1 within the casting mold 7 the clearance gap between such stopping and withdrawing head and the mold Walls is now sealed by returning the previously shifted mold walls into their casting position.

By placing the seal or sealing means 2 in its sealing position between the mold walls and the stopping and withdrawing head prior to the time that the mold walls are returned into their casting position there is gained the important advantage that there can be eliminated the heretofore required time-consuming ramming of the seal into the clearance gap. The seal itself is adjusted by deformation, as best seen by referring to FIG. 3, to the clearance gap of the joint between the stopping and withdrawing head and the mold walls when at least two mold walls are moved back into their casting position, as indicated by arrows 17 in FIG. 3. In this way a reliable sealing effect is insured. Especially when using a seal requiring no chill scrap the creation of the seal is substantially simplified and the time used for creating the seal can be very considerably shortened. A particularly useful form of seal structure which can be employed in the practice of this invention has been disclosed in the commonly assigned, copending US. Pat. Application Ser. No. 225,148, filed Feb. 10, 1972, and entitled Method Of And Means For Sealing A Stopping And Withdrawing Head In A continuous Casting Mold For steel to which reference may be readily had.

As already indicated above, the introduction or application of the seal may be carried out when the stopping and withdrawing head 8 has reached its predetermined position in the continuous casting mold 7. However, and as previously also explained, with advantage the stopping and withdrawing head 8 may be provided with the seal 2 before being moved into position and the seal is then carried into the continuous casting mold 7 while mounted at location 3 on the stopping and withdrawing head 8. During introduction of the seal 2 by the advancing stopping and withdrawing head 8 it must be protected against damage and during this operation there must be prevented undesirable deformation of the seal as otherwise the seal might not then be able to fulfill its intended sealing function.

Further details of the inventive method for sealing the stopping and withdrawing head in a continuous casting mold will now be described in conjunction with a particular illustrative embodiment. It is to be assumed that a slab is to be cast from steel in a continuous casting mold which is adjustable to different slab formats or cross-sections and which continuous casting mold has, for instance, one side which is fixed. The movable mold walls for forming the hallow mold cavity can be shifted in directions perpendicular to the casting axis 21 by hydraulic actuator cylinders 10, 11 and thus adjusted to the desired cross-section of the casting. These mold walls are initially withdrawn away from the casting axis and the stopping and withdrawing head 8 is then introduced into the thus enlarged cavity 9 of the mold 7. During the preceeding pour the stopping and withdrawing head 8 has been kept in readiness and provided with a seal 2 outside the path of the casting.

This seal 2 preferably consists of an asbestos cord containing metallic penetration-retarding elements in the form of wires of soft steel and distributed throughout the interior of the cross-section of such seal. Seals of this type require no special protection by chill scrap because the wires prevent damaging penetration of the steel into the seal until the steel in the neighborhood of the seal has solidified or frozen. The seal itself does not constitute subject matter of this development since, as above-explained, same has been disclosed in the previously referred to commonly assigned, copending United States Application, entitled Method Of And Means For Sealing A Stopping And Withdrawing Head In A Continuous Casting Mold For Steel. During the introduction of the stopping and withdrawing head 8 the seal 2 is protected by a protective covering or cap, for instance a sheet metal hood, placed over the top of the stopping and withdrawing head and the seal so that such seal can not be damaged by the guiding elements. As soon as the stopping and withdrawing head 8 carrying the seal 2 has reached its prescribed position inside the mold 7 the protective cap or hood is removed and the mold walls are returned into their respective positions for casting. As best seen by referring to FIG. 3 the mold walls deform the original cross-section of the seal 2 which then adjusts itself to the clearance gap 20 of the joint, thereby producing the same sealing effect as if an asbestos cord had been rammed into position, but without the cumbersome and time-consuming workwhich would then have been necessary to perform such seal ramming operation.

The invention is not limited in scope to the abovedescribed examples and may also be applied to continuous casting molds having at least two adjustable adjoining mold walls which only serve for solving the contemplated problem.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,

What is claimed is:

1. A method of sealing the stopping and withdrawing head in a continuous casting mold having movable walls defining the cross-section of the mold cavity, said walls of the mold being adjusted to the casting crosssection and a seal is introduced into the clearance gap between the stopping and withdrawing head and the mold walls, the improvement comprising-the steps of withdrawing from their casting position at least two adjoining mold walls in a direction away from the longitudinal casting axis, transferring the stopping and withdrawing head into its prescribed position within the continuous casting mold, and sealing the clearance gap between the stopping and withdrawing head by means of a seal provided thereat and the mold walls by returning the mold walls into position for casting and into contact with the seal, contact of the seal with the mold walls only occurring upon returning of the mold walls into said position for casting.

2. The method as defined in claim ll, including the step of providing the seal at the stopping and withdrawing head prior to the time that said stopping and withdrawing head is introduced into the continuous casting mold.

3. The method as defined in claim 1, including the step of providing the seal after the stopping and withwith penetration-retarding elements inside its crosssection.

6. A method of sealing the stopping and withdrawing head of a dummy bar in a continuous casting mold, comprising the steps of displacing movable mold wall means of the continuous casting mold from a casting position in a direction away from the longitudinal casting'axis to open the continuous casting mold, introducing the dummy bar into the opened casting mold until the stopping and withdrawing head thereof has assumed a prescribed position within the open continuous casting mold, and with a sealing member located at the clearance gap intermediate the stopping and withdrawing head and the wall means of the continuous casting mold, and sealing the clearance gap between the stopping and withdrawing head and the mold wall means via said sealing member by returning the movable mold wall means into position for casting and into contact with said seal member, contact of the sealing member with the mold wall means only occurring after returning of the movable mold wall means into said position for casting.

7. The method as defined in claim 6, including the step of introducing the dummy bar into the open casting mold devoid of any guide means acting upon the portion of the dummy bar located within the open continuous casting mold.

8. The method as defined in claim 6, including the step of applying the sealing member to the stopping and withdrawing head prior to the time the latter is introduced into the continuous casting mold.

9. The method as defined in claim 6, including the step of locating the sealing member at the clearance gap after introduction of the stopping and withdrawing head into the continuous casting mold.

10. A method of sealing the stopping and withdrawing head in a continuous casting mold having movable walls defining the cross-section of the mold cavity, said walls of the mold being adjusted to the casting crosssection and a seal is introduced into the clearance gap between the stopping and withdrawing head and the mold walls, the improvement comprising the steps of withdrawing from their casting position at. least two adjoining mold walls in a direction away from the longitu- I dinal casting axis, transferring the stopping and withdrawing head without the seal contacting the mold walls into its prescribed position within the continuous casting mold, and sealingthe clearance gap between the stopping and withdrawing head and the mold walls by returning the mold walls into position for casting and into contact with the seal to deform the same so as. to seal such clearance gap, contact of the seal with the mold walls only occurring upon returning of the mold walls into said position for casting. 

1. A method of sealing the stopping and withdrawing head in a continuous casting mold having movable walls defining the crosssection of the mold cavity, said walls of the mold being adjusted to the casting cross-section and a seal is introduced into the clearance gap between the stopping and withdrawing head and the mold walls, the improvement comprising the steps of withdrawing from their casting position at least two adjoining mold walls in a direction away from the longitudinal casting axis, transferring the stopping and withdrawing head into its prescribed position within the continuous casting mold, and sealing the clearance gap between the stopping and withdrawing head by means of a seal provided thereat and the mold walls by returning the mold walls into position for casting and into contact with the seal, contact of the seal with the mold walls only occurring upon returning of the mold walls into said position for casting.
 2. The method as defined in claim 1, including the step of providing the seal at the stopping and withdrawing head prior to the time that said stopping and withdrawing head is introduced into the continuous casting mold.
 3. The method as defined in claim 1, including the step of providing the seal after the stopping and withdrawing head has been introduced into the continuous casting mold.
 4. The method as defined in claim 1, including the step of protecting the seal against damage during its introduction into the continuous casting mold.
 5. The method as defined in claim 1, including the step of employing as the seal an asbestos cord provided with penetration-retarding elements inside its cross-section.
 6. A method of sealing the stopping and withdrawing head of a dummy bar in a continuous casting mold, comprising the steps of displacing movable mold wall means of the continuous casting mold from a casting position in a direction away from the longitudinal casting axis to open the continuous casting mold, introducing the dummy bar into the opened casting mold until the stopping and withdrawing head thereof has assumed a prescribed position within the open continuous casting mold, and with a sealing member located at the clearance gap intermediate the stopping and withdrawing head and the wall means of the continuous casting mold, and sealing the clearance gap between the stoppIng and withdrawing head and the mold wall means via said sealing member by returning the movable mold wall means into position for casting and into contact with said seal member, contact of the sealing member with the mold wall means only occurring after returning of the movable mold wall means into said position for casting.
 7. The method as defined in claim 6, including the step of introducing the dummy bar into the open casting mold devoid of any guide means acting upon the portion of the dummy bar located within the open continuous casting mold.
 8. The method as defined in claim 6, including the step of applying the sealing member to the stopping and withdrawing head prior to the time the latter is introduced into the continuous casting mold.
 9. The method as defined in claim 6, including the step of locating the sealing member at the clearance gap after introduction of the stopping and withdrawing head into the continuous casting mold.
 10. A method of sealing the stopping and withdrawing head in a continuous casting mold having movable walls defining the cross-section of the mold cavity, said walls of the mold being adjusted to the casting cross-section and a seal is introduced into the clearance gap between the stopping and withdrawing head and the mold walls, the improvement comprising the steps of withdrawing from their casting position at least two adjoining mold walls in a direction away from the longitudinal casting axis, transferring the stopping and withdrawing head without the seal contacting the mold walls into its prescribed position within the continuous casting mold, and sealing the clearance gap between the stopping and withdrawing head and the mold walls by returning the mold walls into position for casting and into contact with the seal to deform the same so as to seal such clearance gap, contact of the seal with the mold walls only occurring upon returning of the mold walls into said position for casting. 